Angular frequency, or angular speed, corresponds to the rotation speed in a circular motion. It is measured as the rate of change of angles in units of radians per second.
Since sinusoidal wave can be interpreted as projection of circular motion, angular frequency is also often used in the context of waves, oscillations, and Fourier analysis.
The relationship between the angular frequency
Sometimes angular frequency is loosely referred to as “frequency,” though this use can lead to confusing.